The present invention relates generally to a vehicle suspension system including a stabilizer bar with a protrusion which interacts with actively controlled pin stops to control vehicle roll, the pins stops being activated when a sensor detects a roll value greater than a threshold level of roll.
Vehicles are commonly equipped with suspension systems for absorbing road shock and other vibrations, while providing for a smooth and comfortable ride. A suspension component, such as a stabilizer bar, is often used to increase roll rigidity and improve the steering stability of the vehicle. The stabilizer bar is generally attached to the lower A-arms of the suspension system and controls sway as the vehicle turns and provides a pull down force during cornering. This is especially important in sports utility vehicles, which have a higher tendency to roll when the driver attempts an emergency maneuver due to the high center of gravity.
As a vehicle turns, the body of the vehicle rolls to the outside of the turn. The suspension components on the outside of the turn are generally compressed, while the suspension components on the inside of the turn are generally extended. The stabilizer bar counters this motion by pushing up on the suspension components collapsed and compressing the suspension components expanded through torsion in the stabilizer bar.
During cornering, it is desirable that the stiffness of the stabilizer bar be increased. If the stabilizer bar is too compliant, the vehicle will not respond well during cornering, increasing the likelihood of rolling over. However if the stabilizer bar is too stiff, the ride and handling will be compromised during normal vehicle operation. Therefore, it is desirable that the stiffness of the stabilizer bar be variable to adjust for changing driving conditions.
In one proposed vehicle suspension system, a pair of selectively activated variable clamping devices clamp the stabilizer bar to the vehicle body. When a roll sensor detects vehicle roll above a predetermined threshold, a solenoid valve actuates at least one of the clamping devices to provide an actuator force on the stabilizer bar, varying the torsional length of the stabilizer bar. In this prior system, the actuator force is provided by fluid which flows into chambers in the clamping device. As the flow of fluid increases, the actuator force on the stabilizer increases, stiffening the stabilizer bar. This system is undesirably complicated.
This invention relates to a vehicle suspension system including a stabilizer bar which interacts with actively controlled pin stops to prevent vehicle roll.
A stabilizer bar of a vehicle suspension system is received in an aperture in a housing mounted to the body of the vehicle. A pair of activatable pin stops are positioned in the housing to control the stiffness of the stabilizer bar. The stabilizer bar includes a protrusion which during normal vehicle operation is positioned between the pair of pin stops. A spring positioned about each pin provides a retaining spring force on the head of the pin, preventing the pin from gaining access to the aperture of the housing during normal vehicle operation.
During vehicle operation, a sensor monitors a ride parameter, such as lateral a ration or yaw rate. When the sensor detects that the value of the ride parameter exceeds a threshold value, the sensor activates an actuator, such as a solenoids, to drive the pins. The actuator force overcomes the retaining spring force, activating the pins and pushing the body of the pins into the aperture.
When the pins are activated, the protrusion of the stabilizer bar is trapped between the pins, restricting rotation of the stabilizer bar. When the stabilizer bar twists and the protrusion of the stabilizer bar contacts one of the pins, further twist of the stabilizer bar is resisted, increasing the stiffness of the stabilizer bar and preventing roll-over.
Accordingly, the present invention provides a vehicle suspension system including a stabilizer bar which interacts with actively controlled pin stops to prevent vehicle roll.